The standard input device for controlling cursor movement and other operator functions on personal computers and related computer applications is the computer mouse. Prior art computer mouse design has evolved into several various forms and methods of operation. The typical means is by a generally palm-sized device that mimics the general shape of the underside of the hand, allowing for the computer operator's arm and wrist to impart two dimensional movement of the mouse on a flat surface that translates into the two dimensional movement of the cursor on the computer screen. Finger operated switches for cursor activation and special computer functions are typically operated by the first two fingers from the thumb. A “scroll wheel” device is usually positioned roughly between these two switch controls for paging control of documents amongst other things. More recent embodiments of the prior art samples eliminate the mechanical motion sensing mechanism that requires traction-based contact with a mouse pad surface, replacing this with a light-based optical sensing mechanism. Other embodiments have incorporated a wireless connection to transmit control signals between the wireless mouse and the target computer, eliminating the physical wire connection that may inhibit proper mouse operation.
Use of the prior art computer mouse requires that the operator continuously move the mouse across the two-dimensional mouse pad surface located immediately to the right of the keypad for right-handed operators (to the left side for left-handed operators) in motions directly related to the desired two-dimensional movement of the cursor on the computer screen. The controlling hand of the mouse operator generally rests across the top of the mouse, but often the operator's hand may contact or even rest on the mouse pad at the wrist location with the weight of the hand, wrist and forearm upon the point of contact. Continued operation of the mouse requires repetitive movements in any and all directions along the horizontal plane represented by the computer mouse pad or contact surface. The position of the operator's hand while operating the mouse device may impart varying degrees of pressure and various degrees of deflection on the wrist area.
A growing issue with the use of the computer mouse is the incidence of Repetitive Strain Injury (RSI), also referred to as Cumulative Trauma Disorder (CTD), Occupational Overuse Syndrome, or Work Related Upper Limb Disorder (WRULD), One particular manisfistation is Carpal Tunnel Syndrom. All are products of repetitive motion situations where improper ergonomic technique and inadequate design and/or workstation configuration can lead to discomfort in the short run and strain and injury in the long run. This can result in a reduction of worker productivity, and ultimately in chronic pain, quality of life issues, high costs for medical care and medical leave of absense. There are now general standards of practice for workplace ergonomic convention aimed at minimizing the possible onset of RSI as well as various other discomforts and stresses to the body from extended periods of workstation activity. These programs incorporate both training and use of ergonomically designed workstation equipment. Primary to improved ergonomic standard are the various embodiments of prior art ergonomic mouse configurations, each representing varying degrees of benefit. Prior art ergonomic solutions may offer taller mouse body shapes to help reduce the potential for stress upon the wrist. Others may incorporate a more vertically oriented griping structure to rotate the hand into a more comfortable vertical position of reduced wrist pronation. However, the preceding examples still require the mouse operator to engage in repetitive movement of the mouse across a flat surface to manipulate the cursor. Another prior art ergonomic mouse embodiment replaces repetitive movement of the mouse for cursor control with a “track ball” feature in which movement of a spherical device by the thumb controls cursor placement while the mouse body remains stationary. However, the trackball solution still requires substantial and exaggerated repetitive movement of the thumb to operate, leading to the likelihood of operator discomfort and possible development of RSI. An option for cursor control where a mouse may not be usable or space does not permit, such as with a laptop computer, is the miniature joystick or control “nub,” which is comparable in size to a pencil head eraser. This device as previously incorporated within a laptop computer keyboard requires only the slightest movement by an operator's finger for cursor operation. One embodiment of this device is represented by application Ser. No. 08/685,486 filed on Jul. 24, 1996.
The fault with prior-art ergonomic mouse design is primarily two-fold: 1) it presumes the mouse operator will engage in proper ergonomic form for sitting at a workstation when holding and operating the mouse in order to obtain the greatest degree of ergonomic benefit, and 2) it does not provide for a solution in which all operators can achieve optimal hand, wrist and forearm positioning while operating the mouse for maximum ergonomic benefit under all possible workstation conditions. Application Ser. No. 11/349,751, filed Feb. 8, 2006, specifies a similar approach incorporating the pedestal and articulation features of the current art but for an entirely different goal focused on advanced cursor control function with ergonomic considerations subordinate to this feature. In fact, the referenced device requires that the mouse operator engage in significant rocking motions of the mouse body controller to enable cursor movement, resulting in potentially complex and continuous wrist motion and deflections. With the multitude of prior art ergonomic mouse designs on the market, computer mouse operator discomfort and RSI cases continue to be a serious problem still in need of a viable solution.